The present invention relates to an X-ray radiographic/fluoroscopic apparatus, X-ray radiographic method and X-ray radiographic/fluoroscopic method, and more particularly to an X-ray radiographic/fluoroscopic apparatus, X-ray radiographic method and X-ray radiographic/fluoroscopic method that can consistently produce X-ray radiographic images with high quality regardless of the magnitude of body thickness or motion of an examined site.
FIG. 1 illustrates the configuration of an example of a conventional X-ray radiographic/fluoroscopic apparatus.
The X-ray radiographic/fluoroscopic apparatus 500 comprises an X-ray tube 51 in which a single fluoroscopic focus size or a single radiographic focus size is set, an irradiation condition determining section 55 for determining fluoroscopic irradiation conditions and radiographic irradiation conditions (such as the tube voltage and tube current of the X-ray tube 51, exposure dose and radiographic irradiation time), an irradiation control section 57 for controlling the operation of the X-ray tube 51, an imaging section 8 comprising an image intensifier or TV camera or the like for capturing an X-ray fluoroscopic image or X-ray radiographic image of a subject and outputting a fluoroscopic video signal Vf or radiographic video signal Vs, and a display section 9 for displaying an X-ray fluoroscopic image or X-ray radiographic image based on the fluoroscopic video signal Vf or radiographic video signal Vs.
FIG. 2 is a flow chart illustrating an X-ray radiographic/fluoroscopic process by the X-ray radiographic/fluoroscopic apparatus 500.
In Step T1, a subject is irradiated with X-rays based on predefined fluoroscopic irradiation conditions, and an X-ray fluoroscopic image is produced and displayed. The fluoroscopic focus size is 0.3 mm, for example, and the input power rating of the X-ray tube 51 in this case is on the order of 10 kW (or less), for example.
In Step T2, body thickness is calculated based on the X-ray fluoroscopic image to determine radiographic irradiation conditions from the body thickness. The radiographic focus size is 0.6 mm, for example, and the input power rating of the X-ray tube 51 in this case is on the order of 30-40 kW, for example.
In Step T3, the subject is irradiated with X-rays using the determined radiographic irradiation conditions, and an X-ray radiographic image is produced and displayed.
Generally, when the X-rays are emitted from the X-ray tube 51 with a large focus size, an umbra and penumbra of the X-rays tend to simultaneously appear on the image plane, and the image resolution is liable to be degraded. Therefore, the focus size is preferably made small for improved resolution.
On the other hand, when the focus size is small, the input power rating of the X-ray tube 51 is reduced, and hence the radiographic irradiation time (imaging time) required for the same exposure dose is prolonged, leading to a problem that the image is subject to blurring in radiographing an examined site having a large body thickness or large motion. Especially when the gastric wall is radiographed with a contrast material such as barium applied, blurring gets worse due to vibration of the X-ray tube 51 or the gastric wall and rundown of the barium from the gastric wall etc.
It is an object of the present invention to provide an X-ray radiographic/fluoroscopic apparatus, X-ray radiographic method and X-ray radiographic/fluoroscopic method that can consistently produce X-ray radiographic images with high quality regardless of the magnitude of the body thickness or motion of an examined site.
In accordance with a first aspect of the present invention, there is provided an X-ray radiographic/fluoroscopic apparatus comprising: X-ray emitting means having a function of emitting X-rays with a focus selected from at least one fluoroscopic focus size and a plurality of radiographic focus sizes; X-ray fluoroscopic image producing means for producing an X-ray fluoroscopic image by irradiating a subject with X-rays with the fluoroscopic focus size selected; radiographic focus size selecting means for selecting a relatively large radiographic focus size in radiographing an examined site having a relatively large body thickness, and selecting a relatively small radiographic focus size in radiographing an examined site having a relatively small body thickness; and X-ray radiographic image producing means for producing an X-ray radiographic image by irradiating the subject with X-rays equivalent to radiographic irradiation conditions determined based on the X-ray fluoroscopic image with the selected radiographic focus size.
In accordance with a second aspect of the present invention, there is provided an X-ray radiographic/fluoroscopic apparatus comprising: X-ray emitting means having a function of emitting X-rays with a focus selected from at least one fluoroscopic focus size and a plurality of radiographic focus sizes; X-ray fluoroscopic image producing means for producing an X-ray fluoroscopic image by irradiating a subject with X-rays with said fluoroscopic focus size selected; radiographic focus size selecting means for selecting a relatively large radiographic focus size in radiographing an examined site having a relatively large motion, and selecting a relatively small radiographic focus size in radiographing an examined site having a relatively small motion; and X-ray radiographic image producing means for producing an X-ray radiographic image by irradiating the subject with X-rays equivalent to radiographic irradiation conditions determined based on said X-ray fluoroscopic image with said selected radiographic focus size.
In accordance with a third aspect of the present invention, there is provided an X-ray radiographic/fluoroscopic apparatus comprising: X-ray emitting means having a function of emitting X-rays with a focus selected from at least one fluoroscopic focus size and a plurality of radiographic focus sizes; examined site input means for receiving an examined site from an operator; radiographic irradiation time threshold defining means for defining a radiographic irradiation time threshold that is an upper limit of a radiographic irradiation time corresponding to said examined site; X-ray fluoroscopic image producing means for producing an X-ray fluoroscopic image by irradiating a subject with X-rays with said fluoroscopic focus size selected; radiographic focus size selecting means for selecting a relatively large radiographic focus size if a radiographic irradiation time determined based on said X-ray fluoroscopic image is longer than said radiographic irradiation time threshold, and selecting a relatively small radiographic focus size if said determined radiographic irradiation time is shorter than said radiographic irradiation time threshold; and X-ray radiographic image producing means for producing an X-ray radiographic image by irradiating the subject with X-rays with said selected radiographic focus size.
In accordance with a fourth aspect of the present invention, there is provided an X-ray radiographic/fluoroscopic apparatus comprising: X-ray emitting means having a function of emitting X-rays with a focus selected from at least one fluoroscopic focus size and a plurality of radiographic focus sizes; X-ray fluoroscopic image producing means for producing an X-ray fluoroscopic image by irradiating a subject with X-rays with said fluoroscopic focus size selected; radiographic irradiation time threshold input means for receiving from an operator a radiographic irradiation time threshold that is an upper limit of a radiographic irradiation time corresponding to an examined site; radiographic focus size selecting means for selecting a relatively large radiographic focus size if a radiographic irradiation time determined based on said X-ray fluoroscopic image is longer than said radiographic irradiation time threshold, and selecting a relatively small radiographic focus size if said determined radiographic irradiation time is shorter than said radiographic irradiation time threshold; and X-ray radiographic image producing means for producing an X-ray radiographic image by irradiating the subject with X-rays equivalent to radiographic irradiation conditions determined based on said X-ray fluoroscopic image with said selected radiographic focus size.
In accordance with a fifth aspect of the present invention, there is provided an X-ray radiographic/fluoroscopic apparatus comprising: X-ray emitting means having a function of emitting X-rays with a focus selected from at least one fluoroscopic focus size and a plurality of radiographic focus sizes; examined site input means for receiving an examined site from an operator; X-ray fluoroscopic image producing means for producing an X-ray fluoroscopic image by irradiating a subject with X-rays with said fluoroscopic focus size selected; radiographic irradiation condition determining means for determining radiographic irradiation conditions based on said X-ray fluoroscopic image; radiographic focus size selecting means for selecting a radiographic focus size for use in X-ray radiography based on said examined site and said radiographic irradiation conditions; and X-ray radiographic image producing means for producing an X-ray radiographic image by irradiating the subject with X-rays equivalent to said radiographic irradiation conditions with said selected radiographic focus size.
In accordance with a sixth aspect of the invention, there is provided the X-ray radiographic/fluoroscopic apparatus of the above configuration, wherein the X-ray emitting means has a plurality of fluoroscopic focus sizes.
In accordance with a seventh aspect of the invention, there is provided the X-ray radiographic/fluoroscopic apparatus as defined by any one of the claims wherein said X-ray emitting means has three or more radiographic focus sizes.
In accordance with a eighth aspect of the present invention, there is provided an X-ray radiographic method comprising the step of producing an X-ray radiographic image by irradiating a subject with X-rays with a relatively large radiographic focus size in radiographing an examined site having a relatively large body thickness, and by irradiating the subject with X-rays with a relatively small radiographic focus size in radiographing an examined site having a relatively small body thickness.
In accordance with a ninth aspect of the present invention, there is provided an X-ray radiographic method comprising the step of producing an X-ray radiographic image by irradiating a subject with X-rays with a relatively large radiographic focus size in radiographing an examined site having a relatively large motion, and by irradiating the subject with X-rays with a relatively small radiographic focus size in radiographing an examined site having a relatively small motion.
In accordance with a tenth aspect of the invention, there is provided the X-ray radiographic method of the above configuration, wherein the radiographic focus size for use in radiography is selected from among three or more radiographic focus sizes.
In accordance with a eleventh aspect of the present invention, there is provided an X-ray radiographic/fluoroscopic method comprising the steps of: producing an X-ray fluoroscopic image by irradiating a subject with X-rays with a fluoroscopic focus size; selecting a relatively large radiographic focus size from among a plurality of radiographic focus sizes in radiographing an examined site having a relatively large body thickness, and selecting a relatively small radiographic focus size in radiographing an examined site having a relatively small body thickness; and producing an X-ray radiographic image by irradiating the subject with X-rays equivalent to radiographic irradiation conditions determined based on said X-ray fluoroscopic image with said selected radiographic focus size.
In accordance with a twelfth aspect of the present invention, there is provided an X-ray radiographic/fluoroscopic method comprising the steps of: producing an X-ray fluoroscopic image by irradiating a subject with X-rays with a fluoroscopic focus size; selecting a relatively large radiographic focus size from among a plurality of radiographic focus sizes in radiographing an examined site having a relatively large motion, and selecting a relatively small radiographic focus size in radiographing an examined site having a relatively small motion; and producing an X-ray radiographic image by irradiating the subject with X-rays equivalent to radiographic irradiation conditions determined based on said X-ray fluoroscopic image with said selected radiographic focus size.
In accordance with a thirteenth aspect of the present invention, there is provided an X-ray radiographic/fluoroscopic method comprising the steps of: producing an X-ray fluoroscopic image by irradiating a subject with X-rays with a fluoroscopic focus size; receiving an examined site from an operator to define a radiographic irradiation time threshold that is an upper limit of a radiographic irradiation time corresponding to said examined site; selecting a relatively large radiographic focus size from among a plurality of radiographic focus sizes if a radiographic irradiation time determined based on said X-ray fluoroscopic image is longer than said radiographic irradiation time threshold, and selecting a relatively small radiographic focus size if said determined radiographic irradiation time is shorter than said radiographic irradiation time threshold; and producing an X-ray radiographic image by irradiating the subject with X-rays equivalent to radiographic irradiation conditions determined based on said X-ray fluoroscopic image with said selected radiographic focus size.
In accordance with a fourteenth aspect of the present invention, there is provided an X-ray radiographic/fluoroscopic method comprising the steps of: producing an X-ray fluoroscopic image by irradiating a subject with X-rays with a fluoroscopic focus size; receiving from an operator a radiographic irradiation time threshold that is an upper limit of a radiographic irradiation time corresponding to an examined site; selecting a relatively large radiographic focus size from among a plurality of radiographic focus sizes if a radiographic irradiation time determined based on said X-ray fluoroscopic image is longer than said radiographic irradiation time threshold, and selecting a relatively small radiographic focus size if said determined radiographic irradiation time is shorter than said radiographic irradiation time threshold; and producing an X-ray radiographic image by irradiating the subject with X-rays equivalent to radiographic irradiation conditions determined based on said X-ray fluoroscopic image with said selected radiographic focus size.
In accordance with a fifteenth aspect of the present invention, there is provided an X-ray radiographic/fluoroscopic method comprising the steps of: producing an X-ray fluoroscopic image by irradiating a subject with X-rays with a fluoroscopic focus size; determining radiographic irradiation conditions based on said X-ray fluoroscopic image; selecting a radiographic focus size for use in X-ray radiography from among a plurality of radiographic focus sizes based on an examined site and said radiographic irradiation conditions; and producing an X-ray radiographic image by irradiating the subject with X-rays equivalent to said radiographic irradiation conditions with said selected radiographic focus size.
In accordance with a sixteenth aspect of the invention, there is provided the X-ray radiographic/fluoroscopic method of the above configuration, wherein the radiographic focus size for use in radiography is selected from among three or more radiographic focus sizes.
According to the X-ray radiographic/fluoroscopic apparatus of the first aspect, X-ray radiographic method of the eighth aspect and X-ray radiographic/fluoroscopic method of the eleventh aspect, when an examined site having a relatively large body thickness is radiographed, the radiography is performed with a relatively large radiographic focus size selected, whereby the X-ray irradiation strength is enhanced and the radiographic irradiation time reduced to reduce blurring of the examined site. When an examined site having a relatively small body thickness is radiographed, the radiography is performed with a relatively small radiographic focus size selected, whereby the resolution of the X-ray radiographic image is improved.
Consequently, X-ray radiographic images can be consistently produced with high quality regardless of the body thickness.
According to the X-ray radiographic/fluoroscopic apparatus of the second aspect, X-ray radiographic method of the ninth aspect and X-ray radiographic/fluoroscopic method of the twelfth aspect, when an examined site having a relatively large motion is radiographed, the radiography is performed with a relatively large radiographic focus size selected, whereby the X-ray irradiation strength is enhanced and the radiographic irradiation time reduced to reduce blurring of the examined site. When an examined site having a relatively small motion is radiographed, the radiography is performed with a relatively small radiographic focus size selected, whereby the resolution of the X-ray radiographic image is improved.
Consequently, X-ray radiographic images can be consistently produced with high quality regardless of the magnitude of motion of the examined site.
According to the X-ray radiographic/fluoroscopic apparatus of the third aspect and X-ray radiographic/fluoroscopic method of the thirteenth aspect, since a shorter radiographic irradiation time threshold is defined for an examined site having a larger degree of body thickness or motion, when an examined site having a relatively large body thickness or motion is radiographed, a relatively large radiographic focus size is selected and blurring of the examined site can be reduced. When an examined site having a relatively small body thickness or motion is radiographed, a relatively small radiographic focus size is selected and an X-ray radiographic image can be produced with high resolution.
According to the X-ray radiographic/fluoroscopic apparatus of the fourth aspect and X-ray radiographic/fluoroscopic method of the fourteenth aspect, the operator can finely specify a radiographic irradiation time threshold in conformity with image quality preferences or clinical interest while viewing an X-ray fluoroscopic image.
According to the X-ray radiographic/fluoroscopic apparatus of the fifth aspect and X-ray radiographic/fluoroscopic method of the fifteenth aspect, since the radiographic focus size for use in X-ray radiography is selected based on an examined site and radiographic irradiation conditions, X-ray radiographic images can be consistently produced with high quality regardless of the magnitude of body thickness or motion of the examined site.
According to the X-ray radiographic/fluoroscopic apparatus of the sixth aspect, since the fluoroscopic focus size for use in fluoroscopy can be selected from among a plurality of fluoroscopic focus sizes, image quality of the X-ray fluoroscopic image can be improved.
According to the X-ray radiographic/fluoroscopic apparatus of the seventh aspect, X-ray radiographic method of the tenth aspect and X-ray radiographic/fluoroscopic method of the sixteenth aspect, since the radiographic focus size for use in radiography can be selected from among three or more radiographic focus sizes, a radiographic focus size suitable for radiography of the examined site can be more finely selected.
Thus, according to the X-ray radiographic/fluoroscopic apparatus, X-ray radiographic method and X-ray radiographic/fluoroscopic method of the present invention, since the radiographic focus size is changed with the magnitude of body thickness or motion of the examined site, an advantage resulting from magnification of the radiographic focus size (i.e., reduction of blurring by reducing the irradiation time) and an advantage resulting from reduction of the radiographic focus size (i.e., improvement of resolution by suppressing penumbra formation) can be simultaneously obtained in a good proportion, and X-ray radiographic images can be stably obtained with high quality.
Further objects and advantages of the present invention will be apparent from the following description of the preferred embodiments of the invention as illustrated in the accompanying drawings.